/*
 * contrib/btree_gist/btree_ts.c
 */
#include "postgres.h"

#include <limits.h>

#include "btree_gist.h"
#include "btree_utils_num.h"
#include "utils/builtins.h"
#include "utils/datetime.h"

typedef struct
{
    Timestamp    lower;
    Timestamp    upper;
} tsKEY;

/*
** timestamp ops
*/
PG_FUNCTION_INFO_V1(gbt_ts_compress);
PG_FUNCTION_INFO_V1(gbt_tstz_compress);
PG_FUNCTION_INFO_V1(gbt_ts_fetch);
PG_FUNCTION_INFO_V1(gbt_ts_union);
PG_FUNCTION_INFO_V1(gbt_ts_picksplit);
PG_FUNCTION_INFO_V1(gbt_ts_consistent);
PG_FUNCTION_INFO_V1(gbt_ts_distance);
PG_FUNCTION_INFO_V1(gbt_tstz_consistent);
PG_FUNCTION_INFO_V1(gbt_tstz_distance);
PG_FUNCTION_INFO_V1(gbt_ts_penalty);
PG_FUNCTION_INFO_V1(gbt_ts_same);


#ifdef USE_FLOAT8_BYVAL
#define TimestampGetDatumFast(X) TimestampGetDatum(X)
#else
#define TimestampGetDatumFast(X) PointerGetDatum(&(X))
#endif


static bool
gbt_tsgt(const void *a, const void *b, FmgrInfo *flinfo)
{
    const Timestamp *aa = (const Timestamp *) a;
    const Timestamp *bb = (const Timestamp *) b;

    return DatumGetBool(DirectFunctionCall2(timestamp_gt,
                                            TimestampGetDatumFast(*aa),
                                            TimestampGetDatumFast(*bb)));
}

static bool
gbt_tsge(const void *a, const void *b, FmgrInfo *flinfo)
{
    const Timestamp *aa = (const Timestamp *) a;
    const Timestamp *bb = (const Timestamp *) b;

    return DatumGetBool(DirectFunctionCall2(timestamp_ge,
                                            TimestampGetDatumFast(*aa),
                                            TimestampGetDatumFast(*bb)));
}

static bool
gbt_tseq(const void *a, const void *b, FmgrInfo *flinfo)
{
    const Timestamp *aa = (const Timestamp *) a;
    const Timestamp *bb = (const Timestamp *) b;

    return DatumGetBool(DirectFunctionCall2(timestamp_eq,
                                            TimestampGetDatumFast(*aa),
                                            TimestampGetDatumFast(*bb)));
}

static bool
gbt_tsle(const void *a, const void *b, FmgrInfo *flinfo)
{
    const Timestamp *aa = (const Timestamp *) a;
    const Timestamp *bb = (const Timestamp *) b;

    return DatumGetBool(DirectFunctionCall2(timestamp_le,
                                            TimestampGetDatumFast(*aa),
                                            TimestampGetDatumFast(*bb)));
}

static bool
gbt_tslt(const void *a, const void *b, FmgrInfo *flinfo)
{
    const Timestamp *aa = (const Timestamp *) a;
    const Timestamp *bb = (const Timestamp *) b;

    return DatumGetBool(DirectFunctionCall2(timestamp_lt,
                                            TimestampGetDatumFast(*aa),
                                            TimestampGetDatumFast(*bb)));
}


static int
gbt_tskey_cmp(const void *a, const void *b, FmgrInfo *flinfo)
{
    tsKEY       *ia = (tsKEY *) (((const Nsrt *) a)->t);
    tsKEY       *ib = (tsKEY *) (((const Nsrt *) b)->t);
    int            res;

    res = DatumGetInt32(DirectFunctionCall2(timestamp_cmp, TimestampGetDatumFast(ia->lower), TimestampGetDatumFast(ib->lower)));
    if (res == 0)
        return DatumGetInt32(DirectFunctionCall2(timestamp_cmp, TimestampGetDatumFast(ia->upper), TimestampGetDatumFast(ib->upper)));

    return res;
}

static float8
gbt_ts_dist(const void *a, const void *b, FmgrInfo *flinfo)
{
    const Timestamp *aa = (const Timestamp *) a;
    const Timestamp *bb = (const Timestamp *) b;
    Interval   *i;

    if (TIMESTAMP_NOT_FINITE(*aa) || TIMESTAMP_NOT_FINITE(*bb))
        return get_float8_infinity();

    i = DatumGetIntervalP(DirectFunctionCall2(timestamp_mi,
                                              TimestampGetDatumFast(*aa),
                                              TimestampGetDatumFast(*bb)));
    return (float8) Abs(INTERVAL_TO_SEC(i));
}


static const gbtree_ninfo tinfo =
{
    gbt_t_ts,
    sizeof(Timestamp),
    16,                            /* sizeof(gbtreekey16) */
    gbt_tsgt,
    gbt_tsge,
    gbt_tseq,
    gbt_tsle,
    gbt_tslt,
    gbt_tskey_cmp,
    gbt_ts_dist
};


PG_FUNCTION_INFO_V1(ts_dist);
Datum
ts_dist(PG_FUNCTION_ARGS)
{
    Timestamp    a = PG_GETARG_TIMESTAMP(0);
    Timestamp    b = PG_GETARG_TIMESTAMP(1);
    Interval   *r;

    if (TIMESTAMP_NOT_FINITE(a) || TIMESTAMP_NOT_FINITE(b))
    {
        Interval   *p = palloc(sizeof(Interval));

        p->day = INT_MAX;
        p->month = INT_MAX;
        p->time = PG_INT64_MAX;
        PG_RETURN_INTERVAL_P(p);
    }
    else
        r = DatumGetIntervalP(DirectFunctionCall2(timestamp_mi,
                                                  PG_GETARG_DATUM(0),
                                                  PG_GETARG_DATUM(1)));
    PG_RETURN_INTERVAL_P(abs_interval(r));
}

PG_FUNCTION_INFO_V1(tstz_dist);
Datum
tstz_dist(PG_FUNCTION_ARGS)
{
    TimestampTz a = PG_GETARG_TIMESTAMPTZ(0);
    TimestampTz b = PG_GETARG_TIMESTAMPTZ(1);
    Interval   *r;

    if (TIMESTAMP_NOT_FINITE(a) || TIMESTAMP_NOT_FINITE(b))
    {
        Interval   *p = palloc(sizeof(Interval));

        p->day = INT_MAX;
        p->month = INT_MAX;
        p->time = PG_INT64_MAX;
        PG_RETURN_INTERVAL_P(p);
    }

    r = DatumGetIntervalP(DirectFunctionCall2(timestamp_mi,
                                              PG_GETARG_DATUM(0),
                                              PG_GETARG_DATUM(1)));
    PG_RETURN_INTERVAL_P(abs_interval(r));
}


/**************************************************
 * timestamp ops
 **************************************************/


static inline Timestamp
tstz_to_ts_gmt(TimestampTz ts)
{
    /* No timezone correction is needed, since GMT is offset 0 by definition */
    return (Timestamp) ts;
}


Datum
gbt_ts_compress(PG_FUNCTION_ARGS)
{
    GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);

    PG_RETURN_POINTER(gbt_num_compress(entry, &tinfo));
}


Datum
gbt_tstz_compress(PG_FUNCTION_ARGS)
{
    GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
    GISTENTRY  *retval;

    if (entry->leafkey)
    {
        tsKEY       *r = (tsKEY *) palloc(sizeof(tsKEY));
        TimestampTz ts = DatumGetTimestampTz(entry->key);
        Timestamp    gmt;

        gmt = tstz_to_ts_gmt(ts);

        retval = palloc(sizeof(GISTENTRY));
        r->lower = r->upper = gmt;
        gistentryinit(*retval, PointerGetDatum(r),
                      entry->rel, entry->page,
                      entry->offset, FALSE);
    }
    else
        retval = entry;

    PG_RETURN_POINTER(retval);
}

Datum
gbt_ts_fetch(PG_FUNCTION_ARGS)
{
    GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);

    PG_RETURN_POINTER(gbt_num_fetch(entry, &tinfo));
}

Datum
gbt_ts_consistent(PG_FUNCTION_ARGS)
{
    GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
    Timestamp    query = PG_GETARG_TIMESTAMP(1);
    StrategyNumber strategy = (StrategyNumber) PG_GETARG_UINT16(2);

    /* Oid        subtype = PG_GETARG_OID(3); */
    bool       *recheck = (bool *) PG_GETARG_POINTER(4);
    tsKEY       *kkk = (tsKEY *) DatumGetPointer(entry->key);
    GBT_NUMKEY_R key;

    /* All cases served by this function are exact */
    *recheck = false;

    key.lower = (GBT_NUMKEY *) &kkk->lower;
    key.upper = (GBT_NUMKEY *) &kkk->upper;

    PG_RETURN_BOOL(
                   gbt_num_consistent(&key, (void *) &query, &strategy, GIST_LEAF(entry), &tinfo, fcinfo->flinfo)
        );
}

Datum
gbt_ts_distance(PG_FUNCTION_ARGS)
{
    GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
    Timestamp    query = PG_GETARG_TIMESTAMP(1);

    /* Oid        subtype = PG_GETARG_OID(3); */
    tsKEY       *kkk = (tsKEY *) DatumGetPointer(entry->key);
    GBT_NUMKEY_R key;

    key.lower = (GBT_NUMKEY *) &kkk->lower;
    key.upper = (GBT_NUMKEY *) &kkk->upper;

    PG_RETURN_FLOAT8(
                     gbt_num_distance(&key, (void *) &query, GIST_LEAF(entry), &tinfo, fcinfo->flinfo)
        );
}

Datum
gbt_tstz_consistent(PG_FUNCTION_ARGS)
{
    GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
    TimestampTz query = PG_GETARG_TIMESTAMPTZ(1);
    StrategyNumber strategy = (StrategyNumber) PG_GETARG_UINT16(2);

    /* Oid        subtype = PG_GETARG_OID(3); */
    bool       *recheck = (bool *) PG_GETARG_POINTER(4);
    char       *kkk = (char *) DatumGetPointer(entry->key);
    GBT_NUMKEY_R key;
    Timestamp    qqq;

    /* All cases served by this function are exact */
    *recheck = false;

    key.lower = (GBT_NUMKEY *) &kkk[0];
    key.upper = (GBT_NUMKEY *) &kkk[MAXALIGN(tinfo.size)];
    qqq = tstz_to_ts_gmt(query);

    PG_RETURN_BOOL(
                   gbt_num_consistent(&key, (void *) &qqq, &strategy, GIST_LEAF(entry), &tinfo, fcinfo->flinfo)
        );
}

Datum
gbt_tstz_distance(PG_FUNCTION_ARGS)
{
    GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
    TimestampTz query = PG_GETARG_TIMESTAMPTZ(1);

    /* Oid        subtype = PG_GETARG_OID(3); */
    char       *kkk = (char *) DatumGetPointer(entry->key);
    GBT_NUMKEY_R key;
    Timestamp    qqq;

    key.lower = (GBT_NUMKEY *) &kkk[0];
    key.upper = (GBT_NUMKEY *) &kkk[MAXALIGN(tinfo.size)];
    qqq = tstz_to_ts_gmt(query);

    PG_RETURN_FLOAT8(
                     gbt_num_distance(&key, (void *) &qqq, GIST_LEAF(entry), &tinfo, fcinfo->flinfo)
        );
}


Datum
gbt_ts_union(PG_FUNCTION_ARGS)
{
    GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
    void       *out = palloc(sizeof(tsKEY));

    *(int *) PG_GETARG_POINTER(1) = sizeof(tsKEY);
    PG_RETURN_POINTER(gbt_num_union((void *) out, entryvec, &tinfo, fcinfo->flinfo));
}


#define penalty_check_max_float(val) do { \
        if ( val > FLT_MAX ) \
                val = FLT_MAX; \
        if ( val < -FLT_MAX ) \
                val = -FLT_MAX; \
} while(false);


Datum
gbt_ts_penalty(PG_FUNCTION_ARGS)
{
    tsKEY       *origentry = (tsKEY *) DatumGetPointer(((GISTENTRY *) PG_GETARG_POINTER(0))->key);
    tsKEY       *newentry = (tsKEY *) DatumGetPointer(((GISTENTRY *) PG_GETARG_POINTER(1))->key);
    float       *result = (float *) PG_GETARG_POINTER(2);

    double        orgdbl[2],
                newdbl[2];

    /*
     * We are always using "double" timestamps here. Precision should be good
     * enough.
     */
    orgdbl[0] = ((double) origentry->lower);
    orgdbl[1] = ((double) origentry->upper);
    newdbl[0] = ((double) newentry->lower);
    newdbl[1] = ((double) newentry->upper);

    penalty_check_max_float(orgdbl[0]);
    penalty_check_max_float(orgdbl[1]);
    penalty_check_max_float(newdbl[0]);
    penalty_check_max_float(newdbl[1]);

    penalty_num(result, orgdbl[0], orgdbl[1], newdbl[0], newdbl[1]);

    PG_RETURN_POINTER(result);

}


Datum
gbt_ts_picksplit(PG_FUNCTION_ARGS)
{
    PG_RETURN_POINTER(gbt_num_picksplit(
                                        (GistEntryVector *) PG_GETARG_POINTER(0),
                                        (GIST_SPLITVEC *) PG_GETARG_POINTER(1),
                                        &tinfo, fcinfo->flinfo
                                        ));
}

Datum
gbt_ts_same(PG_FUNCTION_ARGS)
{
    tsKEY       *b1 = (tsKEY *) PG_GETARG_POINTER(0);
    tsKEY       *b2 = (tsKEY *) PG_GETARG_POINTER(1);
    bool       *result = (bool *) PG_GETARG_POINTER(2);

    *result = gbt_num_same((void *) b1, (void *) b2, &tinfo, fcinfo->flinfo);
    PG_RETURN_POINTER(result);
}
